Advances in Chemical Engineering and Science, 2011, 1, 245-251 doi:10.4236/aces.2011.14035 Published Online October 2011 (http://www.SciRP.org/journal/aces) Copyright © 2011 SciRes. ACES Pretreatment of Wastewater Streams from Petroleum/Petrochemical Industries Using Coagulation Hossam Altaher * , Emad ElQada, Waid Omar Chemical Engineering Technology Department, Yanbu Industrial College, Saudi Arabia E-mail: * haltaher@hotmail.com (or haltaher@vt.edu) Received June 27, 2011; revised July 19, 2011; accepted August 12, 2011 Abstract Coagulation-flocculation processes using different types of conventional coagulants, namely, ferric chloride (FeCl 3 ), aluminum sulfate (AL 2 (SO4) 3 ·18H 2 O), lime and ferrous sulfate (FeSO 4 ) were investigated using the Jar-test technique. A further aim is to determine the optimum conditions for the treatment of industrial wastewater effluents i.e. coagulant dosage, mixing rate, temperature and pH control. Under optimal condi- tion of process parameters, coagulation/flocculation process was able to lower the turbidity well below the permissible level (1.8 NTU). The results indicate that ferric chloride had superior efficiency compared with other coagulants with efficient dose of 800 mg/l. The optimal initial pH of the effluents that enhanced the turbidity removal was 8.6. The temperature showed no significant effect on the turbidity removal. Keywords: Ferric Chloride, Coagulation, Wastewater, Petrochemicals, Pretreatment 1. Introduction This template, Yanbu Industrial City, at the Red Sea Coast of Saudi Arabia, is considered as one of the major industrial cities in the Kingdom of Saudi Arabia. The city accommodates several large refining and petro- chemical plants as well as a broad range of other manu- facturing and support enterprises [1]. This inexorable growth in the scale of the petrochemical industries and oil refinery was largely responsible for the remarkable ecological problems at Yanbu Industrial City. This forces the Saudi government to issue strict legis- lation concerning the quality of industrial wastewater effluents and the industries are not allowed to discharge any treated or untreated effluent in open channels and even after treatment, the reclaimed water must have to comply with direct discharge standards before discharge to the sea [2]. So the entire industrial sectors send their wastewater effluents to a local wastewater treatment plant to treat their waste effluents to an increasingly high standard. Actually, the treatment system consisting of physical, chemical, and biological units is not enough in its current state to reach the permissible levels of dis- charge especially for turbidity. However, the focus of this paper is the enhancement of coagulation process in an attempt to comply with turbidity standards for obvi- ous health issues. Coagulation, adsorption on activated carbon, precipi- tation, evaporation, ion-exchange, oxidation, and bio- degradation and membrane filtration are known as an industrial pollution prevention technology and used for the decontamination of contaminated water and waste- water [3]. According to Renault et al. [3], complete treatment will clearly require several steps and it is often appropriate to combine several methods of purification before maximal efficiency is obtained. Coagulation/flocculation is a widely-used process in the primary purification of water and in industrial wastewater treatment [3-5]. This method has a prefer- ence in the primary purification processes mainly due to the ease of operation, high efficiency, cost effective Also, it uses less energy than alternative treatment [5-7]. Coagulants, both inorganic and organic such as alu- minum sulfate (alum), ferrous sulfate, ferric chloride and ferric chloro-sulfate are widely used as coagulants in water and wastewater treatment for removing a broad range of impurities from effluent, including organic mat- ter, turbidity, color, microorganism, colloidal particles and dissolved organic substances [4,5,8-10] Wang et al [11] demonstrated that many factors can influence the efficiency of coagulation-flocculation pro- cess such as the type and dosage of coagulant/floccu- lant, pH, mixing speed and time, temperature and reten- tion time. An appropriate combination of these factors is